1. Field of the Invention
The present invention relates to an improved photoengraving machine used to engrave stamping faces using photoengraving technology with high efficiency, low cost and low pollution.
2. Description of Related Art
Photoengraving is an advanced method of engraving stamping faces because of its high efficiency. As shown in FIGS. 6 to 8, a flash light (51) is provided in a lower portion of a conventional photoengraving machine (50). A positive film (41) with text or images should be aligned with an opening (421) in a positioning frame (42) and glued onto the positioning frame (42). The opening (421) of the positioning frame (42) is formed to conform to the stamping face of a stamp. The positive film (41) glued on the positioning frame (42) is placed first on a glass plate (40) provided in the photoengraving machine (50) above the flash light (51). Then a carbon film (43) is placed on the positive film (41), and a thin ethylene-vinyl acetate EVA, sheet (44) the size of the opening (421) in the positioning frame (42) is placed on the carbon film (43) for test engraving. A pressing apparatus (46) is placed on the thin EVA sheet (44), and a top cover (52) of the photoengraving machine (50) is closed to be ready for a flash. The engraved thin EVA sheet (44) should be examined, and an adjustment of the positive film (41) may be made to ensure that the text and images are aligned with the opening (421) of the positioning frame (42).
After the test with the thin EVA sheet, a thick EVA sheet (45) is mounted with a new carbon film (43) between the positive film (41) and the thick EVA sheet (45). Then the pressing apparatus (46) is placed on the thick EVA sheet (45), and the top cover (52) is closed to be ready for a formal photoengraving.
The engraved thick EVA sheet (45) should be mounted on a stamp as a stamping face and bonded to the stamp by a sheet of polyethylene (PE) on an electric heater.
The following are a number of shortcomings that exist with the conventional photoengraving machine.
1. The process of photoengraving a stamping face is complex. As the precision of aligning the positive film with the stamping face is difficult to control, the thick EVA sheet used in the formal engraving should have a margin left around the engraved area. The margin is cut after photoengraving to ensure the alignment of the text and images on the stamping face.
2. The quality of the photoengraving is dependent on the experience of skilled workers.
3. The photoengraved stamping face should be bonded on a stamp, and the bonded surfaces should be tested before filling the stamp with ink to ensure that ink will not leak around the edges of the stamping face.
Therefore, it is an objective of the invention to provide an improved photoengraving machine for stamping face to mitigate and/or obviate the aforementioned problems.